Thermophilic denitrification of tobacco

Abstract

High temperature processes and thermophilic organisms for use in those processes for reducing the levels of certain nitrogen-containing compounds in tobacco materials. Tobacco materials are contacted with at least one thermophilic organism characterized by an anaerobic, dissimilatory, metabolic pathway for denitrification of tobacco materials under anaerobic and high temperature conditions that promote such metabolism. Tobacco materials treated in accordance with these high temperature processes and thermophilic organisms, when incorporated into a smoking product, deliver a significantly reduced amount of oxide of nitrogen in smoke. Moreover, such tobacco materials also afford the product of other tobacco products having lower amounts of nitrates and other nitrogen-containing compounds.

We claim: 
     
       1. A process for the denitrification of tobacco materials, comprising the step of contacting said tobacco materials, which have not been terminally sterilized, with at least one thermophilic organism characterized by an anaerobic, dissimilatory, metabolic pathway for denitrification of tobacco materials under anaerobic and high temperature conditions, of above about 45° C., that promote such metabolism, wherein said temperature is maintained without cooling. 
     
     
       2. The process according to claim 1, wherein said tobacco materials are selected from the group consisting of whole tobacco leaf, cut or chopped tobacco, reconstituted tobacco, tobacco stems, shreds, fines and combinations thereof. 
     
     
       3. The process according to claim 1 or 2, wherein said tobacco materials are first extracted with water to produce an aqueous tobacco extract having a nitrate-nitrogen content of from about 10 ppm to more than about 10,000 ppm and said extract is then contacted with said organisms. 
     
     
       4. The process according to claim 1 or 2, wherein said tobacco materials are first suspended in water to form a slurry having a concentration of about 5% to about 40% solids by weight and said slurry is then contacted with said organisms. 
     
     
       5. The process according to claim 4, wherein said tobacco materials are first suspended in water to form a slurry having a concentration of about 5% to about 20% solids by weight and said slurry is then contacted with said organisms. 
     
     
       6. The process according to claim 1 or 2 wherein said tobacco materials are first sprayed with water to form a tobacco having sufficient water for growth of said organisms and said tobacco is then contacted with said organisms. 
     
     
       7. The process according to claim 6 wherein said water also contains from about 1% to about 5% of a carbon source. 
     
     
       8. The process according to claim 1, wherein said anaerobic and thermophilic conditions include a temperature of between about 45° C. and about 65° C. 
     
     
       9. The process according to claim 1, wherein said anaerobic and thermophilic conditions include a pH of between about 5 and about 10. 
     
     
       10. The process according to claim 9, wherein said pH is between about 7 and about 8.5. 
     
     
       11. The process of claim 1, wherein said thermophilic organisms are selected from the group consisting of thermophilic organisms belonging to the usual microflora of tobacco materials, thermophilic organisms from other sources, mutations of such organisms and combinations thereof, all such organisms being characterized by an anaerobic, dissimilatory, metabolic pathway for denitrification of tobacco materials under anaerobic and high temperature conditions that promote such metabolism. 
     
     
       12. The process of claim 11, wherein said thermophilic organsism are selected from the group consisting of PM-1, PM-2, PM-3, PM-4, biotypes of Bacillus circulans and Bacillus licheniformis, mutations of such organisms and combinations thereof, all such organisms being characterized by the anaerobic, dissimilatory, metabolic pathway for denitrification of tobacco materials under anaerobic and high temperature conditions that promote such metabolism.